First Goal - Radiation Studies: A) Development of model of staged radiation injury (using new UCSD Radiotherapy Unit). B) Complete study of already harvested rat and human radiation tissues via electron microscopy to explain ultrastructure of radiation injury. C) Collect and study actinic radiation-damaged human tissues; delineate common "elastotic" fibers in actinic and therapeutic radiation damage. D) Develop model of skin flap delay in rats, to find if flap delay in radiated tissue increases flap survival (a major clinical problem in radiation ulcer repair). Second Goal - Drug Therapy of Contraction: A) Develop model of possible inhibition of contraction using prostaglandin inhibitors (planned with help of Upjohn Company). B) Electron microscopy of this model if successful, to delineate mechanism of effect.